The dreaded Failed Update message. If you click “Get help with this error” for this one, you won’t get any help. Luckily, if you encounter Windows Update Error 20000009 notification, there is a quick solution.
When trying to install a massive SQL Server update KB2958429, this error appeared and the server update failed because the C: Drive was out of space.
Increase the size of your C Drive and the updates will work just fine.